连铸长水口钢水保护浇注耐火制品｜Long Nozzle for Continuous Casting
中文部分
连铸长水口是钢水保护浇注的关键部位，其耐火材料选型直接影响产品质量、生产效率和设备寿命。在实际应用中，常见的选材误区包括忽视水口内部温度梯度、忽略钢水冲刷磨损机理，以及对高铝质耐火材料的过度依赖。根据我的多年一线经验，长水口耐材选型应从以下几个维度考虑：
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工况匹配与材料性能
长水口的核心要求是高温稳定性、抗渣蚀和抗冲刷能力。针对不同钢种（如高碳钢、合金钢），应选择碳化硅-碳复合材料（SiC-SiC）或高铝质刚玉砖（Al₂O₃≥90%）。前者适用于高温氧化环境，后者则更耐碱性渣侵蚀。例如，某钢厂采用SiC-SiC水口后，钢水温度下降率降低至3℃/t，延长了水口使用寿命至120天左右。 -
踩坑与实操建议
我曾见过工厂错误地选择普通高铝砖替代高性能耐火材料，导致水口在30天内严重磨损，甚至出现渣流入钢包的事故。实操建议：
- 测试阶段：先用低碳化硅耐火浇注料进行试水口，观察渣流情况，避免高成本材料浪费。
- 维修频率：定期检查水口内部温度分布，发现局部过热时及时更换局部损坏的部位。
- 工厂落地与成本平衡
不同耐材的成本差异显著，但性能提升带来的经济效益远大于成本。例如，一家钢厂采用碳化硅复合材料替代传统高铝砖后，每吨钢的能耗降低约20%，年节约成本约100万元。但需要注意的是，过度追求高性能材料会导致设备维护成本上升，应根据实际需求进行权衡。
English Translation
Long Nozzle for Continuous Casting
The long nozzle in continuous casting is the critical zone for steel protection during pouring, and its refractory material selection directly impacts product quality, production efficiency, and equipment lifespan. In practice, common selection mistakes include ignoring temperature gradients inside the nozzle, overlooking steel erosion mechanisms, and over-relying on high-alumina refractories. Based on my years of firsthand experience, the selection of long nozzle refractories should consider the following aspects:
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Matching Work Conditions and Material Performance
The core requirement for long nozzles is high-temperature stability, resistance to slag erosion, and erosion resistance. For different steel types (such as high-carbon steel and alloy steel), silicon carbide-silicon carbide composite materials (SiC-SiC) or high-alumina corundum bricks (Al₂O₃ ≥ 90%) should be selected. The former is suitable for high-temperature oxidation environments, while the latter is better at resisting alkaline slag erosion. For example, a steel plant using SiC-SiC nozzles reduced steel temperature loss to 3°C/t, extending nozzle life to about 120 days. -
Common Pitfalls and Practical Recommendations
I have witnessed cases where plants incorrectly replaced high-performance refractories with ordinary high-alumina bricks, leading to severe wear within 30 days and even slag entering the ladle. Practical recommendations include:
- Testing Phase: Use low-carbonized pouring refractories for trial nozzles to observe slag flow and avoid wasting high-cost materials.
- Maintenance Frequency: Regularly check temperature distribution inside the nozzle; replace damaged sections promptly if local overheating is detected.
- On-Site Implementation and Cost Balance
The cost difference between different refractories is significant, but the performance improvements yield far greater economic benefits. For instance, a steel plant replacing traditional high-alumina bricks with silicon carbide composites reduced energy consumption per ton of steel by 20%, saving approximately 1 million yuan annually. However, it is important to note that overemphasizing high-performance materials can increase equipment maintenance costs. A balanced approach based on actual needs is essential.
